And what about a demo record?
Well, as the Doc said: it's just a recording of a song before it's been done "properly" in the studio.
But just to expand on that, there's two main uses for them. Firstly, a demo is a sort of rough draft or early sketch, but in audio/musical format. It's meant to be a basic outline of how a songwriter "sees" a particular song, and it's presented to himself and other people for further creative input. Secondly, musicians often use demos to present themselves to professional studios/producers, to give those people an idea of what it is they'd be working with. In this sense, it's kind of like an audition or a screen test.